Process of making dialyzing and pervaporating membranes and product produced thereby



Patented Oct. 28, 1930 {PATENT-V o FicE,

PHILIP Anon: KQBEB, or CHICAGO, ILLINOIS rnocnssor MAKING IJIALY'ZINQ nn risnvarone'rme MEMBRANES AND rnonuo'r H rnonUoEnT EREBY No Drawing. Original application filed June 17, 1918, SerialNo. 240,468. Divided and this application 1 4 filed November as, 192s. seriarnd. 151,02'1'.

This invention relates to'improvements in the manufacture and composition of mem branes and membrane containers, -usable in the well known art of'dialyzi-ng and in'the fi well known art of pervaporationands pers 5 class consists of; those made: from' 'coll'odion I and gelatine and similar-solutions. The

crystallization, described in the Journal of the American Chemical Society, vol. 39, page 944, (1917); z This' application is a division of my 'copendin'g application 'S'GIlflllJ-NOL'E l-3240, 168, filed June 17,1 9 18; 1'

Tliemembranes-usually madeand .for

these arts ma :be divided into: tWfllQlfiSSS. 1. The first class consists ofrpa-rchmentpaper and certain natural niembrans.-.: ,flhe second class of membranes-can .beflusedwover and over again, but have the disadvantage-of ;be-..

ing difiicultly. shaped into various forms,

3.such as bottles, flasks,'tubes,;etc. .The second class of membranes can lie-shaped ormoulded into almost any form; buticollodion containers cannot be used over-wand over-agaimwhile gelatine membranesare too fragile for most purposes.

It is also well known that collodion membranes shrink enormously-and become hard and impermeable when subjected to drying. in partorinwhole. c.

I observed that gelatine, jellos and jellies in domestic use, although containing much water in their composition do not dry or shrivel up, no matter how long they stand at room temperatures. It,therefore,occurred ,to me that if I could make a gel from collodion and gelatine, it would solve the problem, and give us a membrane which could be moulded or shaped as desired, which would not shrink and could be used over and over again.

grams of gelatine are-dissolved in another Then the two solutions are mixed until homogeneous. Mother proportions can be also used to advantage, such as'l part collodion.

vand 3 tov 4: parts ofgelatine, or '2: parts=of 'collodionand 1 part of gelatinea; After thorough mixing, the collodion-gelatine solution is poured-into the ;mouldof shape. desired. made of glass or any other suitable material:

j, On evaporation of the solvent either by blowingair through: the mouldor shapetby pres.-

sure or by suction or allowing spontaneous evaporation the layer of collodion gelatine remains as a hard'mjembrane. qAfter removing most of t-heso'lvent i-nfth'e manner-indicated the membrane is then treated With'wa- F ter, whereupon the membrane imbibes water andbecomes a gel. It is then usa-blefor dialyzing 'or pervaporation orany other useful purpose. 1

:It was then found that peptones could be substituted for gelatine in this composition and similar results obtained. The collodione Y e 'toneel membranes also aossess the no erty' of percrystallization, which the collodion-gelatine-gelmembranes do, not seem to possess.

Itv will be observed that my invention and discovery shows that proteinsor protein like products or derivatives, found nnature or,

made in the laboratory fromproteins by digestion or hydrolysis, may be found suitable to mix .with collodion or similar cellulose compounds, which havea'eommon acid solvent; Y It will be understood, therefore, that this invention will not be limited to anypar-T ticular cellulose. or nitro-cellulose compound, nor'any particular protein or protein derivative, or digestion or hydrolysis product of protein, (all of which have the aminc or imino grouping capable of forming acid salts with acids), nor limited to any particular acid solvent, nor the relativeainount of solvent used. It is obvious to those skilled in the art that any acid such as butyric acid. if cheap enough could be substituted for acetic aci That this method of making membranes allows those skilled in the art to vary the permeability by varying the concentrations of one or the other constituents'or both, is obvious from the literature on the subject of membrane permeability, and will be understood to flow from this disclosure. Under the term protein substance used in the claims, I intend to include all proteins, protein derivatives, digestion products of protein, hydrolysis products of protein, and the like, having an amino or iminogrouping capable of forming salts with acids.

The term homogeneous mixture as used in'the appended claims will be understood as having its ordinary meaning except inso-- far as it is used in defining the composition including the imbibitory liquid (e. g. Water) lVhen so used, it is to be understood as meaning that water has been imbibed by the membrane formed from a homogeneous mixture of the cellulose derivative and the protein substance so as to be substantially uniformly distributed therein {hence While in one sense the product or article claimed may be referred to as a homogeneous mixture of the cellulose derivative, the protein substance and water, it is probably more correctly described as a homogeneous mixture of water and the cellulose derivative-protein substance composition.

I claim:

1. The process of making a permeable membrane, consisting in dissolving a cellulose derivative and a protein substance in a common solvent, forming the solution into a membrane by removal of the solvent, and treating the formed membrane with an imbibitory liquid. v

2. The process of making a permeable membrane, consisting in dissolving nitro-cellulose and a protein substance in a common solvent, forming the solution into a membrane by removal of the solvent, and treating the formed membrane with an imbibitory liquid.

3. The process of making a permeable membrane, consisting in dissolving collodion and a protein substance in a common acid solvent, forming the solution into a membrane by removal of the solvent, and treating the formed membrane with water, to cause imbibition thereof by said membrane, thereby imparting permeability to said membrane.

4. The process of making a permeable membrane, consisting in dissolving a cellulose derivative and gelatine in a common solvent, forming the solution into amembrane by removal of the solvent, and treating the formed membrane with an imbibitory liquid.

5. The process of making a permeable membrane, consisting in dissolving nitro-cellulose and gelatine in a common solvent, forming the solution into a membrane by removal of the solvent, and treating the formed membrane with an imbibitory liquid.

6. The process of making a permeable membrane, consisting in dissolving collodion and gelatine in a common acid solvent, forming the solution into a membrane by removal of the solvent, and treating the formed membrane with water, to cause imbibition thereof by said membrane, thereby, imparting permeability to said membrane.

7. The process of making a permeable membrane, comprising dissolving a cellulose derivative and a protein substance in a common solvent, forming a membrane by sub. stantially removing the solvent, and before change decreasing the permeability of the membrane has taken place, treating the formed membrane with an imbibitory liquid.

8. The process of making a permeable membrane, comprising dissolving a nitrocellulose compound and gelatine in a common solvent comprising a carboxylic acid of the aliphatic group, forming a membrane by substantially removing the solvent, and treating the formed membrane before drying with an imbibitory liquid.

9. A permeable membrane composed of a homogeneous mixture comprising a cellulose derivative and a protein substance.

10. .A permeable membrane composed of: a homogeneous mixture comprisingv nitro cellulose and a protein substance.

11. A permeable membrane composed of a homogeneous mixture comprising nitrocellulose and gelatine.

12. A permeable membrane composed of a homogeneous mixture of a cellulose derivative, a protein substance and Water;

13. A permeable membrane'composed of a homogeneous mixture of Intro-cellulose, a protein substance and water. 7

14. A permeable membrane composed of a homogeneous mixture of intro-cellulose, gelatine and Water.

In testimony whereof, I have signed my name to this specification this 22nd day of November, 1926.

PHILIP ADOLPH KOBER. 

